Sfark-plucf



' L. C. LEWIS.

SPARK PLUG.

APPLICATION FILED APR. 23, 1919.

' Patented Nov. 25, 1919.

m/mmm clean and free SPARK-PLUG.

Application filed April as,

To all whom it may concern:

Be it known that I, LEWIs C. LEWIS, a citizen of the UnitedStates, residing at 00- lumbus, in the county of Franklin and State of Ohio, have invented a certain new and useful Improvement in Spark j Plugs, of which the following is a specification.

The object of this invention is more especially to provide a construction inwhich the sparking members are to a large extent kept provide numerous points for sparking so that if one or more points become incapacitated there may be others capable of functioning. v

The invention is embodied in the examples I herein shown and described, the features of novelty being pointed out in the claims.

In the accompanying drawing Figure 1 is a view partly in side elevation and partly 1n central longitudinal section.

Fig. 2 1s a plan view looking at the lower end.

Fig. 3 is a detail sectional view on the line IIIIII Fig. 2 of the-interior sparking member on a larger scale. i f p a The construction includes the plug shell threaded to enter and engage the'head of the engine cylinder, as usual, the porcelain member 6 containing a metallic stem 7 anda nut 8 for holding the porcelain member and stem within the shell. The conductor'stem 7 is provided at its lower end with a metallic circular cup shaped sparking member 9 having its edge deeply and regularly serrated to provide a considerable number of'upwardly pointing sparking points 10. The sparking member 9 is conveniently riveted or otherwise secured to the lower end of the con. ductor 7 with its concave side uppermost as best shown in Fig. 3 so that the points stand upward. The opposing or cooperating sparklng member consists of a grooved or channeled ring 11 welded or otherwise secured to the outer side of the lower end of from oils and carbon and to Specification of Letters Patent. Patented NOV. 25, 1919.

1919. Serial NO. 292,204. I

the shell 5 with its open side uppermost'so that the inner rim of the ring shall present an upwardly standing sparking wall at the proper distance from each of the several sparking points 10. The bottom of the ring 11 is provided with a number of perfora- 'tions 12-to drain the oils and carbon collecting in the cavity of the ring. Because the inner wall of the ring 11 and points 10 are upwardly standing oils drain off them carrying with them the carbon accumulating thereon. Such a construction renders the plug capable of long continued use without attention.

The electrical current is supplied through th'e'usual conductor attached at 13 in electrical connection with the stem 7, said current being grounded in the engine through the shell asusual. I

The forms of the parts can be changed Without departing from the gist of the invention as claimed. v

What I claim is' 1. In a spark plug sparking elements including, in combination, a dished serrated member having its points standing upward and a cooperating grooved ring having its open side uppermost, said grooved ring having a draining aperture. a

In a spark plug sparking elements including, in combination, a dished serrated member having its points standing upward and acooperating grooved ring having its open side uppermost, said grooved ring having a draining aperture and said ring sur-. v roundlng the serrated member.

LEWIS: o. LEWIS. 

